When did Leonardo da Vinci invent the airscrew?

What part of speech is amphibian in this sentence Can an amphibian live in an environment where the temperature is very low? How many atria does the human heart have? Why doesn't the earth's crust become thicker even when a new crust is formed at divergent boundaries? What art period was Andy Warhol part of? If you get paint somewhere you don't want it how can you clean it off if you notice it right away? What happens when you recycle plastic? What mediums did Pablo Picasso use? Is there an artist named J Holland? How do you become a courtroom artist? What does an average cardiac cycle take in seconds? Spark plug gap 1975 302 mustang engine? Is mark salling Jewish? Who was the Green party formed by? Length of the smallest egg by a bird? What is a opposite of a catacombs? Is there a never die cheat in kingdom hearts 1? Who is the square angry bird? When and by whom was the stained glass rendering of the St La Salle made? How many times does the word master appear in the bible? List of nightshade vegetables?